/* Array allocation from a fixed-size buffer.

   Copyright (C) 2017-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <alloc_buffer.h>

#include <malloc-internal.h>

#include <libc-pointer-arith.h>

void *

__libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size,

                                 size_t align, size_t count)

{

  size_t current = buf->__alloc_buffer_current;

  /* The caller asserts that align is a power of two.  */

  size_t aligned = ALIGN_UP (current, align);

  size_t size;

  bool overflow = check_mul_overflow_size_t (element_size, count, &size);

  size_t new_current = aligned + size;

  if (!overflow                /* Multiplication did not overflow.  */

      && aligned >= current    /* No overflow in align step.  */

      && new_current >= size   /* No overflow in size computation.  */

      && new_current <= buf->__alloc_buffer_end) /* Room in buffer.  */

    {

      buf->__alloc_buffer_current = new_current;

      return (void *) aligned;

    }

  else

    {

      alloc_buffer_mark_failed (buf);

      return NULL;

    }

}

libc_hidden_def (__libc_alloc_buffer_alloc_array)